Electric metal-working apparatus.



E. THOMSON.

ELECTRIC METAL WORKING APPARATUS.

APPLICATION FILED APR. 27, 1911. 1,012,934.

Patented Dec. 26, 1911.

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A ELI/IU THOMSON www. 6 Arnmmfrs E. THOMSON. ELECTRIC METAL WORKING APPARATUS. APPLICATION FILED APR. 27, 1911,

Patented Deo. 26, 1911.

2 SEEETS1-SHEET24 /7 TTOH/VEYS UNITED sTATEs PATENT oEEIcE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO THOMSON ELEC- TRIC WELDING COMPANY, OF LYNN, MASSACHUSETTS, A CORPORATION 0F MASSA- CHUSETTS.

Specification of Letters Patent.

App1ication filed April 27, 1911.

ELECTRIC METAL-WORKING APPARATUS.

Patented Dec. 26, 1911.

Serial No. 623,573.

To all whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident of Swampscott, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Electric Metal-Working Apparatus, of which the following is a specication.

My invention relates to that class of electric metal working apparatus in which the metal is softened or brought to the desired degree of plasticity for the welding or other metal working operation by an `electric c urrent applied thereto by suitable weldlng jaws or welding electrodes or other devices constituting electrodes through which heating current is supplied to the section of Work to be heated, suitable means being employed for applying pressure to the heated work or otherwise operating upon it mechanically and also, if desired, for supporting or holding the Work on or independently of the electrodes.

My invention relates particularly to those forms of electric metal working apparatus in which two or more electrodes are fed' .with the heating current from a common supply bar of conducting material charged with energy by attachment of any portion of its length to a suitable source of electromotive force. The invention is particularly useful for machines in which the said supply bar forms a terminal ofthe heavy copper bar or block constituting the secondary of a potential reducing transformer in a manner well-known in the art. I do not however limit myself to a current of any particular form.

The object of my invention is to permit the different electrodes supplying respectively the energy to different pieces of work to feed the same amount of current to all the pieces or different amounts of adjusted values adjusted to the particular amount of,

current desired in each piece of work irrespective of the position ofI the electrode upon the current feed bar.

To these ends my invention consists, genl erally stated, in providing the current supplying bar with arms which carry at their terminations the respective work-engaging electrodes Aand which arms individually have adjusted values of resistance or opposition to the flow of current in them, as will be more particularly hereinafter described'.

In the acompanylng drawings, Figure 1 is a plan of a form of apparatus embodying my invention. Fig. 2 is an elevation of the bar and arms. Fig. 3 is, a cross-section Athrough the longitudinal bars Fig. 1. Fig.

4 is a cross-section through one of the arms and shows the preferred form of the laminated magnetic circuit surrounding said arm to give it inductance. Fig. 5 illustrates a modification of the arms extending from the current supply bar.

1 indicates a heavy bar or rod of copper or other good conducting material forming a terminal of a suitable source of electric energy which is fed thereto by attachment of the source at any portion of the length of the bar.

In the form of my invent-ion illustrated in Fig. 1, said bar is supplied from either or bot-h ends with alternating currents from the secondary of the transformer or transformers 2, 2', and for convenience and to secure rigidity in the machine, said bar forms in effect an extension of the heavy copper secondary bar 3. Opposite said bar 1 and in the desired relation thereto for supporting or feeding currents to the opposite side of the work is another bar 1 which is fed from the other terminal or terminals of the secondary bars of the transformers 2, 2.

From the bar 1 extend arms 4 of any desired number,l each of which carries'or is connected at its terminal to a head or block 4 forming or carrying the electrode which applies current to the work and which head may also afford means for attachment of the devices which clamp the work, or may be itself a welding electrode, as well understood in the art. The arms 4 may be so constructed` as to be iieXible, thus permitting the heads to be freely moved for the purpose of applying pressure to the work and at the same time dispensing with a'ny sliding connection between the feed bar and the work. I prefer to construct the arms from laminations of copper assembled` in a pile or bundle. Movement may be imparted to the heads simultaneously or dissimultaneouslyT by any desired means, as well understood in the art. The complementary heads 'or electrodes carried by the opposite feed bar 1 are marked 6 and may be attached to or form an integral 'partL of thev bar l', which in many commercial utilizations of my invention would be a cast copper bar having the heads or parts 6 castl integrally with it..

, Said heads may carry devices for clamping the Work and supplying current theretoand constitute the opposite electrodes of the apparatus, there being as many of said Aheads 6 as there are heads 4 and each opposed pair serving to supply current to a dierent piece or portion of work for heating the same. The heads 6 might, however, as indicated in Fig. 5, be simply mov-- sistance or inductance being adjusted in value to the amount of -current desired, thereby making it possible to supply to each piece or portion of work currentV of a value independent of the position of each arm or of its corresponding electrode on the feed bar `.1 and independent vof itsdistance from the point of attachment or connection of said current supply bar to the current supply. In the case of alternating currents, the resistance or opposition to the flow of current in each arm andV to each electrode is conveniently secured by surrounding the arm with laminated iron 8, the amount of which as determined by the number of plates in each pile or otherwise, will depend in each case upon the amount of current desired between each pair of electrodes or heads 4, 6'. Preferablyeach magnetic circuit has an air gap as at 8', the effect of which is to steady the current in each arm and obtain a practically constant currenttherein. The value of the different inductances is shown as roughly accommodated to the dierences in distance of the arms from the ends of the supply bar l. Inasmuch as ,the current ,is fedinto the bar from the ends, as shown, the middle arm 4 is provided with less inductance, since the potential of said arm at its point vof connection with the bar -1 -is less than that of thearms nearer the ends of the bar. This would be roughly an -adjustment of inductances designed to give practically the same current values the same between the various pairs of electrodes or heads 4, 6. ItI Vis not necessary, therefore, that the current feed bar should be supplied from both ends since it might be supplied from /one end only as indicated in Fig. 5 and in that caSethe-value ofthe inductances might decrease progresssively from one end to the other,'in order that inductance or resistance to flow of current in the arm nearest the point of attachment to the source should be greater and that more remote should be less, and in a degree to practically equalize the flow of current through all the arms. might have any other relation of values to one another as desired or so as to secure different values of heating current in the different/pieces or portions of work. I do not, therefore, limit myself to providing inductances of values adjusted to give currents of the same value in all of the arms but may apply the inductances to any desired amount and togive any required or desired amount of heating current at each piece or portion of work.

Obviously my invention does not depend upon the order of operation of the welding Vdevices or application of the heating eifect-s, since the apparatus may be operated to heat the pieces or portions of work and applypressure either simultaneously or dissimulaneously and in any desired order or numer. In the modification of my invention shown in Fig. 5 the several arms are shown as solid arms or projections not having Hexibility and said arms may be cast upon the bar l if desired and in one piece therefwith, as shown. Each said bar would, however, as before, be providedfwith the desired and adjusted amount of inductance in lproportion to the current required on each piece or portion of the work. The said `arms are here shown as themselves con-- stitutiung one ofa pair of welding jaws or electrodes, the opposit-e members of each lpair being mounted upon and receiving current from the oppositebar l', so that the work will be compressed-between said members and will, at the same time, be fed with current therefrom. rIhe opposite membersv 6 in this instance are the movable electrodes which are actuated, by any desired means vknown in the arti either simultaneously or in any desired sequence.-

What I claim as my invention is: 1. In an apparatus of the character de-l scribed, a current supplying bar provided Or the inductances vwith arms terminating in electrodes for dif- I lferent pieces or portions of work, said arms having-values of inductance adjusted to disvtribute the current to the work in the desired proportions.

2. In an apparatus of the character described, a .current supplying barA to which.

are attached work supply electrodes fed with currents from said bar adjusted in value with reference to the position of the lelectrode on the bar. i

3. In an apparatus-of the character described, a cur-rent supply bar having armscarrying at their terminals means for feeding current to the Work, said arms being provided With means for opposing the flow of current to the terminals and in proportions adjusted With reference to the po sit-ion. of the arms on the bar and the amount of current desired in each piece or portion of Work.

4. In an electric metal Working apparatus, the combination with a current supply bar, of a series of current supplying blocks or heads deriving current from said bar and connected thereto at different pointsgalong its longitudinal axis and means for adjusting the supply of current to each head With reference to its position on the bar and the current required for the particular piece or portion of work supplied from each head.

5. In an electric metal Working apparatus, the combination -With a series of current carrying heads and a current supply bar therefor, of projections from the bar.

connecting .the same with the heads and laminated iron applied around the projections as and for the purpose described.

6. In an electric metal Working appara-- tus, the combination of a pair of current supply bars and a pair of transformers whose opposite terminals are connected to the ends of said bars respectively, current supplying heads each forming the termination of a projection or arm from `one of said bars and laminated iron on said arms as and for the purpose described.

7. In an electric metal Working apparatus, the combination of a pair of current supply bars provided With a series of electrodes having inductances of adjusted value,

adjusted With relation to the amount of current desired in each piece or portion of the Work.

8. In an electric metal Working apparatus, the combination of an alternating current supply bar, "a series of current supply- `ing electrodes orheads mounted on arms projecting therefrom, said arms being provided With a mass of iron provided with an air gap as and for the purpose described.

9. In an electric metal Working apparatus, a current supply bar having a lateral projection terminating in a Work supplying head or electrode and a mass of laminated iron surrounding said projection and provided vvith an air gap as and for the purpose described.

1Q. In an apparatus of the character described, a current feed bar extending from a terminal of a transformer secondary and provided with a plurality of flexible arms projecting laterally therefrom and having Welding electrodes at their free ends.

11. In an apparatus of the character described, an alternating current feed bar forming a terminal of a transformer secondary and flexible arms projecting laterally therefrom and provided With inductancc. l

Signed at Lynn in the county Of'ESsex and State of Massachusetts this 24th day of April A. D. 1911.

A ELIHU THOMSON.

Witnesses:

JOHN A. MGMANUS, Jr. CHARLES A. BARNARD. 

